This invention relates to an electronic musical instrument and, more particularly, to an electronic musical instrument capable of producing a plurality of musical tones simultaneously and also capable of controlling the pitch, tone color and volume of the respective musical tones in response to "finger touch;" i.e., pressure applied on the keys upon depression thereof, speed of depression and displacement of the keys upon depression thereof.
A function to control musical tones in response to the finger touch (hereinafter referred to as "touch response function") and a function to control musical tones subsequent to this touch (hereinafter referred to as "after-touch control") are both desirable for electronic musical instruments because the player's feeling can be expressed in the reproduced musical tones through these functions. In the prior art electronic musical instruments capable of playing plural tones simultaneously, said touch response and after-touch control functions are performed with respect to each of the keys by providing the same number of touch response control circuits and musical tone generation systems as a total number of keys on the keyboard. This naturally necessitates a large size of apparatus and accompanying high manufacturing costs.